This invention relates to piston assemblies for reciprocating mechanisms such as engines, pumps, compressors, or the like. More specifically, the invention relates to improved means for cooling such pistons.
Prior art of possible relevance includes the following U.S. Pat. Nos.: 2,865,348 issued Dec. 23, 1958 To Kramer et al; 3,221,718 issued Dec. 7, 1965 to Isley; 3,314,402 issued Apr. 18, 1967 to Tillack; and 3,877,351 issued Apr. 15, 1975 to Barfiss.
Constant efforts are being made to improve the construction of pistons employed in reciprocating mechanisms such as internal combustion engines, pumps, compressors, or the like. In many applications, it is necessary that the pistons effectively resist high temperatures which can cause overheating and cracking of the piston and which contribute to the deposit of residues on sealing rings and associated grooves.
In general, the various approaches to improvement can be categorized as improvements in structural design, improvements in metallurgy, and improvements in cooling. The present invention is concerned with the latter and the above identified prior art is exemplary of the state of the art.
One difficulty in providing for improved cooling of pistons is the accomplishing of effective circulation of the coolant fluid, normally lubricating oil, in a simple structure. As can be seen from the above mentioned patents, many structures which provide for good coolant circulation are quite complicated in terms of their structure. Thus, they are disadvantageous in terms of fabrication costs, both from the standpoint of casting various formations or coolant conduits and from the standpoint of assembly where multiple parts are employed. Others, while simple in construction, do not provide for as efficient cooling.
Thus, there is a real need for an improved piston assembly where effective cooling is attained while fabrication costs are minimized.